Lid for auxiliary dust removal receptacle

ABSTRACT

A molded plastic lid for use on an auxiliary trash collection container used with a shop vacuum cleaner or dust collector system. Incoming air and entrained materials are directed along the inside of the container at a shallow angle, and outgoing air is drawn from the center of the lid at a steeper angle. The resulting airflow in the container is a vortex or cyclone-like flow that deposits most of the incoming material within the container, thereby increasing the collection capacity of the system with which the lid is used by the volume of the auxiliary container.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to dust removal systems, shop vacuum cleaners,dust separation devices and auxiliary containers to receive materialscollected by dust removal systems and shop vacuum cleaners.

2. The Prior Art

Shop vacuum cleaners and a substantial variety of sizes andconfigurations of dust removal systems are widely used in homeworkshops, cabinet shops and commercial woodworking facilities for thecollection and removal of sawdust, planer chips, sanding dust, and otherdust and particulate matter produced during operation of suchfacilities. Typical shop vacuum cleaners draw air and waste through aflexible hose into a bucket-like waste collection chamber. There the airis drawn through a filter, typically a pleated filter of nonwovenfibrous material, which catches most of the waste material, allowingrelatively clean air to be discharged. Dust collectors typically utilizea squirrel cage fan that draws air and debris through the fan and into asleeve-like structure oriented vertically so that a cloth wastecollection bag can hang below the structure and air can exit through acloth bag attached to, and which inflated during use above, the sleeve.The capacity of each of these devices is limited to the capacity of therigid bucket-like container in the case of the shop vacuum and the lowerwaste receiving bag or bags in the case of the dust collector.

Efforts have been undertaken to increase the quantity of sawdust andother waste that can be collected using such devices (without emptyingthe waste reservoirs) by drawing the air and collected debris firstthrough or adjacent to an auxiliary waste collection receptacle intowhich some of the waste falls, thereby increasing the overall capacityof the system by the volume of the auxiliary receptacle.

One widely available device to accomplish this is a replacement lidintended to be positioned on top of a trash container or otherreceptacle having an open top. This lid has entrance and exit holes fortubing and a baffle between the entrance and exit so that some of thedust and other debris entrained in an air stream passing through thedevice falls down into the trash container or other receptacle on whichthe device rests. When used with a typical woodworking shop dustcollection system and positioned between the dust collector and thesource of dust, this existing device appears to separate up toapproximately ninety percent of airborne particles which fall into thetrash can on which it is positioned.

SUMMARY OF THE INVENTION

The present invention is a molded plastic lid for use on a twenty inchdiameter trash can or twenty four inch diameter steel drum or othersimilar container, together with a shop vacuum cleaner or a dustcollection system. Air and entrained particles such as saw dust aredrawn into an inlet in the lid, and air is drawn from an outlet in thelid to the conventional shop vacuum cleaner or dust collection system.The inlet is positioned near the rim of the lid and generally tangent tothe rim. The outlet is positioned in the center of the lid. The positionof the inlet directs incoming air and entrained particles into thecontainer near its inside wall and at an angle approximately 25° belowthe vertical plane within which the lid generally sits. Outgoing air isdrawn from the center of the lid at a steeper angle of about 45°. Theresulting airflow induces a vigorous cyclone-like air movement or avortex in the trash container, which generally prevents entrained dustand particles from joining the outgoing airflow. Instead, incoming airtravels in a downward spiral in which centrifugal force preventsparticles from immediately following the outward flow of air. Like theeye of a hurricane, air pressure in the central region below the lid islower then the pressure within the moving air at the periphery of thelid and near the trash container wall. As a result of these airmovements, dust and other incoming particles tend to drop out of the airstream and remain in the trash container, more effectively separatingdust and particles than a conventional baffle-type lid.

The cyclone-like air movement established within a container on whichthe lid of the present invention rests is less turbulent then airflowutilizing a baffle-type lid. This makes the dust removal or vacuumsystem within which the present invention is used more efficient in thatthere is greater airflow with a given exertion of energy than with anotherwise comparable system using a baffle-type lid. The inlets andoutlets of the lid of the present invention can be bored to receive theends of a conventional flexible dust collector hose, such as a four inchdiameter hose. Alternatively, the inlets and outlets can be bored toreceive conventional 2.3 inch diameter shop vacuum hoses and fittings orother desired sizes.

The lid of the present invention has a stepped rim so that it can beused on a conventional trash can having a nominal diameter of twentyinches or on a fifty gallon drum that is typically twenty-four inches indiameter. The stepped structure ensures a tight fit with the lidproperly centered on either size container. The greater air pressure onthe outside of the lid during use with a shop vacuum cleaner or dustremoval system presses down on the lid, effectively sealing it againstthe trash container on which it is mounted.

If the inlet hose attached to the lid of the present invention isblocked or otherwise closed, the resulting reduction in pressure insidethe trash receptacle can cause the generally domed lid of the presentinvention to be forced into the trash container in an "inverted"position like an umbrella that is turned inside out by a strong wind.The lid can easily be popped back the other way, however. The risk ofsuch inversion can also be avoided by providing a small hole in the lid,such as a 0.75 inch diameter hole.

A plastic garbage bag can be used as a removable trash container bag inwhich collected dust can be discarded. In order to prevent such aplastic bag from being drawn toward the lid outlet, the bag can beplaced in the trash container and then generally held in place with asheet of resilient plastic material that is bent into a tube-like form,placed inside the bag, and then permitted to expand or unroll to holdthe bag against the trash container wall.

It yet is thus an object of the present invention to provide forcyclonic dust separation in a trash container.

It is a further object of the present invention to provide foraccommodation of two or more sizes of dust collector hose or vacuumhoses or fittings in an auxiliary container lid.

It is a further object of the present invention to provide a cyclonicaction dust separation lid that seats on at least two diameters ofconventional containers.

It is another object of the present invention to provide, in a cyclonicdust separation lid, inlet and outlet orientation and positioning thatallows for use of the lid and associated trash container in an "in line"hose configuration so that inlet and outlet hoses generally travel inthe same horizontal line.

It is another object of the present invention to provide a trashcontainer lid usable with a wet/dry vacuum cleaner for separation ofwater from a stream of air.

It is further object of the present invention to provide for pressureequalization in a cyclonic-type dust separation lid so that lid will notbe unduly distorted if the vacuum inlet hose is closed or blocked.

It is further object of the present invention to provide for use of adisposable trash bag in a dust container used with a cyclonic-type dustseparation lid.

Finally, it is an object of the present invention to provide aneconomical way of providing an auxiliary dust collecting container foruse with a conventional dust collection system and shop-type vacuumcleaner.

These and other objects of the present invention will become apparent inthe following detailed description of the invention, the accompanyingdrawings and the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the cyclonic-type dust separation lid ofthe present invention shown in use with a shop vacuum cleaner and on topof a generally cylindrical trash container.

FIG. 2 is a plan view of the lid shown in FIG. 1.

FIG. 3 is a sectional view taken along line 3--3 in FIG. 2.

FIG. 4 is a sectional view taken along line 4--4 in FIG. 2.

FIG. 5 is a sectional view similar to FIG. 3 showing a shop vacuumcleaner hose positioned in the outlet of the lid of the presentinvention.

FIG. 6 is a sectional view similar to FIG. 5 showing a larger diameterdust collection hose.

FIG. 7 is an exploded perspective view of the lid of the presentinvention shown together with a metal trash container, a plastic filmtrash bag, and a bag liner to prevent the bag from collapsing duringuse.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the auxiliary trash container lid 10 of the presentinvention positioned on top of a trash container 12 with an inlet hose14 connected to an inlet 16 in lid 10. An outlet hose 18 connects to acentrally located outlet 20 in lid 10. The remote end 22 of outlet hose18 is connected to a conventional shop vacuum cleaner 24. The vacuumhoses 14 and 18 illustrated in FIG. 1 could alternatively be largerdiameter dust collector hoses with a dust collector substituted for theshop vacuum 24.

As it is suggested by the arrows 26 in FIG. 1, air and entrained dustparticles drawn into inlet hose 14 pass through inlet 16 in lid 10 nearits periphery 30 (see FIG. 2) at an angle relative to the plane of thetop edge or lip 32 of trash container 12 (see FIG. 3) so that dust flowsas indicated by arrows 26 in a downward spiral within the generallycylindrical interior of container 12. Dust 28 and other matter entrainedin the airflow 26 generally drops out of the airflow onto the bottom ofcontainer 12. Air containing relatively little entrained matter flows upthe central region of container 12 as indicated by arrows 34, and outthe centrally located outlet 20 of lid 10 through hose 18 to shop vacuumcleaner 24. The air is filtered, typically with a pleated filter, andultimately is discharged by the shop vacuum cleaner 24.

As will be appreciated by reference to the figures, each of the inlet 16and outlet 20 are provided by a hood and scoop arrangement connected bya circular plate. A hood-like structure 36 in the shape of asemi-cylindrical surface rises out of the generally dome-like top 38 oflid 10. A circular plate 40 lies against the projecting hood 38 andterminates the bottom of a scoop 42 that is also in the shape of asemi-cylindrical surface projecting below the doom-like top 38 of lid10.

The dome-like top 38 of lid 10 is circumscribed by a generally verticalband 44 that steps the dome 38 down to a depressed generally horizontalarea 46 that connects step down 44 to a second step down or dependingskirt 48 that forms the largest diameter peripheral edge of lid 10. Thisstep down structure allows lid 10 to be used alternatively on a largerdiameter trash container 12, in which case lip 48 assists in positioningthe lid on the container, or on a smaller diameter container (smallerthan diameter y in FIG. 3) in which case step down 44 assists inpositioning the lid on the container 12. For instance, if diameterxshown in FIG. 3 is a little larger than 24 inches, lid 10 can be used ona typical 50 gallon drum. Likewise, if diameter y shown in FIG. 3 is alittle larger than 20 inches, lid 10 can be used on a conventional trashcontainer 12 that is nominally 20 inches in diameter.

As will be appreciated by reference to FIG. 3, if scoop 42 and hood 36are positioned at a relatively small angle A above the horizontal plane50 of the lid 10 (with plate 42 positioned normal to that angle), inlethose 14 will thereby be located with its longitudinal axis (in thevicinity of lid 10) at approximately same relatively low angle A. Thisangle should be on the order, for instance, of approximately 20-30°,optimally about 25°. This will cause air in the stream 28 to entercontainer 12 at this angle and travel along the inside 52 of container12 in a downward spiral as indicated in arrows 26. By contrast, outlet20 is formed by a hood 54, a scoop 56 and an outlet plate 58 at a largerangle B so that the longitudinal axis of outlet hose 18 where itconnects to outlet 20 of lid 10 will be closer to vertical, therebydrawing air as indicated by arrows 34 in FIG. 1 from the central regionof trash container 12. Angle B should be between approximately 35-55°,preferably between approximately 40-50°, and most preferably atapproximately 45°. Plates 40 and 58 may be bored with holes of anyconvenient diameter to accommodate conventional dust collector systemhoses or shop vacuum cleaner hoses. For instance, diameter C shown inFIGS. 3 and 4 may be four inches for four inch dust collector hoses.Similarly, diameter D on FIGS. 3 and 4 maybe 2.3 inches or any otherdiameter needed to accommodate shop vacuum cleaner hose fittings.

As will be apparent from the figures, particularly including FIGS. 3, 4,5 and 6, the inlet hole 60 and outlet hole 62 (see FIG. 2) should bepositioned with their lowest points near scoops 42 and 56. As FIGS. 5and 6 show, this permits scoops 42 and 56 to support a portion of thehoses 14 and 18 where they attach to lid 10, both ensuring properorientation of the hoses and facilitating their continued connection tolid 10 during use.

As is particularly well illustrated in FIGS. 1, 2 and 7, the generallydome-like shape of lid 10 is reinforced with ribs 64. Ribs 64 may beraised portions of the material from which lid 10 is made that generallyradiate outward from the center of lid 10. These ribs maybe formed inthe spider-like configuration of gently curved rib 64 illustrated in thefigures, but may also be formed in a wide variety of otherconfigurations, or may be made of rods or other materials bonded to lid10. Ribs 64 rigidify lid 10 to facilitate its ability to retain itsdome-like shape under the weight of hoses 14 and 18 and the force of airpressure on the top of lid 10 when the dust collector or shop vacuum 24is on, thereby reducing the air pressure on the underside of lid 10.

As is explained above, when lid 10 is used with a powerful shop vacuumor dust collection system and inlet hose 14 is blocked or closed,external air pressure on the top of lid 10 can press it down into atrash container 12, thereby inverting its dome-like shape,notwithstanding the strength contributed by ribs 64. This can beprevented, however, by forming a relatively small diameter holesomewhere in the lid, which causes internal and external pressure on thelid to be more nearly equal without significantly reducing the capacityof the vacuum or dust collection system to collect debris. Such a holecan be, for instance, a 3/4 inch diameter hole 66 in scoop 56, asillustrated in FIG. 2, an alternative that is practical when arelatively small diameter inlet hose 14 is in use. Alternatively, thehole 66 can be located in any other convenient location in lid 10.

Hole 66 can even be maintained closed during normal use of lid 10without blockage of inlet hole 14 by closing it with structure ormaterial that will open or fail only if the greater pressuredifferential is experienced inside and outside of lid 10 when inlet 14is blocked. For instance, hole 66 could be covered with a weak plasticfilm that would fail in the presence of such a substantial pressuredifferential. It could also be fitted with a spring loaded, evenadjustable, valve that would remain closed until there is such pressuredifferential.

As will be appreciated by those familiar with systems utilizing pressuredifferentials, as do vacuum and dust collector systems, trash container12 needs to be fairly rigid to avoid collapse during use when thecumulative pressure differential between the inside and outside ofcontainer 12 is substantial. Accordingly, auxiliary trash containers 12are typically metal. However, sufficiently rigid plastic containers arealso certainly usable. For similar reasons, a plastic film trash bag orother liner cannot be used inside container 12 unless steps are taken toavoid its collapse during use.

An apparatus permitting the use of a plastic film bag 68 inside of trashcontainer 12 is illustrated in FIG. 7 as resilient plastic sheet 70.Sheet 70 is a generally rectangular sheet of plastic or other materialhaving sufficient rigidity to resist collapse of bag 68 but sufficientbendability to be rolled into a cylindrical shape that fits inside bag68 and presses it against the inside of trash container 12. Sheet 70 mayhave generally oblong cut outs 72 to serve as hand holds to facilitatemanipulation of sheet 70. Dotted lines 74 in FIG. 7 indicate break linesor cutting lines that can be used to shorten sheet 70. Sheet 70 may bemade of a variety of materials including, for instance, polypropylene,polyethylene, high impact polystyrene, acrylonitrile-butadiene-styrene,polyvinylchloride, acrylic or other plastic resin systems.

The lid 10 of the present invention may be formed of a variety ofmaterials including, for instance, formed sheet metal and cast metal. Amore cost effective method of forming lid 10, however, is to mold it ofplastic utilizing, for instance, vacuum forming, thermoforming, high orlow pressure injection molding, compression molding, reaction injectionmolding or other suitable processes, as will be apparant to thoseskilled in the art of plastics manufacturing. Suitable materials usableto manufacture lid 10 include polypropylene, polyethylene, high impactpolystyrene, acrylonitrile-butadiene-styrene, polyvinylchloride, acrylicand other polymer resins and resin systems with or without reinforcingmaterials such as glass or aramid fibers.

As will be appreciated by those skilled in the art, the foregoinginvention can be practiced with a substantial number of variations andmodifications without departing from the scope and spirit of theinvention as described above, in the accompanying drawings and thefollowing claims.

I claim:
 1. A lid for use:(a) on a container having a side attached toor forming a rim that generally lies in a plane and against which thelid may rest; and (b) with a system for drawing air and entrainedmaterial through a hose, the lid comprising a round, generallydome-shaped plate having a center, which plate is penetrated by:(i) aninlet for directing incoming air and entrained material downward andalongside the container side, the inlet comprising an inlet hoodprojecting out of the plate, a scoop recessed below the plate and aninlet panel connecting the hood to the scoop and penetrated by an inlethole to receive an inlet hose positioned at an acute inlet anglerelative to the plane; and (ii) an outlet for exhausting air fromapproximately the center of the lid, the outlet comprising an outlethood projecting out of the plate, a scoop recessed below the plate andan outlet panel connecting the hood to the scoop and penetrated by anoutlet hole to receive an outlet hose positioned at an acute outletangle relative to the plane.
 2. The lid of claim 1, wherein the inletangle is approximately 20 to 30 degrees.
 3. The lid of claim 1, whereinthe inlet angle is approximately 25 degrees.
 4. The lid of claim 1,wherein the outlet angle is approximately 35 to 55 degrees relative tothe plane.
 5. The lid of claim 1, wherein the outlet angle isapproximately 40 to 50 degrees relative to the plane.
 6. The lid ofclaim 1, wherein the outlet angle is approximately 45 degrees relativeto the plane.
 7. The lid of claim 1, further comprising generally radialribs reinforcing the lid.
 8. The lid of claim 1, wherein the materialfrom which the lid is formed comprises acrylonitrile-butadiene-styrene.9. The lid of claim 1, further comprising a pressure relief openingpositioned in the lid to permit airflow therethrough.
 10. The lid ofclaim 1, wherein the peripheral edge of the lid is stepped to form aninner dependent lip having a first diameter and an outer dependent liplarger in diameter than the first lip and connected to the first lip bya generally horizontal web that lies against the rim of the containerwhen the rim is smaller in diameter than the outer lip but larger indiameter than the inner lip.
 11. The lid of claim 1, wherein the inlethole is positioned in the inlet panel proximate the scoop so that thescoop can support a portion of the inlet hose.
 12. The lid of claim 1,wherein the outlet hole is positioned in the outlet panel proximate thescoop so that the scoop can support a portion of the outlet hose.
 13. Alid for use:(a) on a container having a side attached to or forming arim that generally lies in a plane and against which the lid may restand (b) with a system for drawing air and entrained material through ahose, the lid comprising a round, generally dome-shaped molded plasticplate having a center, which plate is penetrated by:(i) an inlet fordirecting incoming air and entrained material downward and alongside thecontainer side, the inlet formed by an inlet hood projecting out of theplate, an inlet scoop recessed below the plate and a generally flat,generally round inlet panel connecting the hood to the scoop andpenetrated by an inlet hole to receive an inlet hose positioned at aninlet angle of approximately 25 degrees relative to the plane, and (ii)an outlet for exhausting air from approximately the center of the lid,the outlet formed by an outlet hood projecting out of the plate, anoutlet scoop recessed below the plate and a generally flat, generallyround outlet panel connecting the hood to the scoop and penetrated by anoutlet hole to receive an outlet hose positioned at an outlet angle ofapproximately 45 degrees relative to the plane.
 14. The lid of claim 13,wherein the inlet hole is positioned in the inlet panel proximate theinlet scoop and the outlet hole is positioned in the outlet panelproximate the outlet scoop so that the scoops can support portions ofhoses connected to the lid.
 15. The lid of claim 13, wherein plasticcomprises acrylonitrile-butadiene-styrene.